1. Field of the Invention
The present invention relates to a frame structure of a small vehicle, in which an abutting surface abutting against a first frame member is provided on a second frame member constituting a part of a vehicle frame together with the first frame member. Furthermore, the second frame member is welded to the first frame member by an outer periphery of the abutting surface.
2. Description of Background Art
Frame structures are disclosed in Japanese Utility Model Laid-Open Publication No. S61 (1986)-15686. One frame structure is configured to weld and couple a down tube to a gusset integrally molded with a head pipe, which a vehicle frame of a motorcycle includes on a front end thereof. Another frame structure includes a gusset having an abutting surface abutting against the head pipe. The gusset is welded to the head pipe by an outer periphery of the abutting surface and a down pipe is welded and coupled to the gusset when the down pipe is coupled to the head pipe with the gusset interposed therebetween.
However, when the head pipe and the gusset are integrally molded, there is a problem in that a molding die is increased in size and becomes complicated to thereby increase the cost of molding. In addition, although the cost of molding does not increase when the gusset is welded to the head pipe, an abutting surface is provided on the gusset so as to abut against the head pipe for the purpose of increasing joining strength of the head pipe and the gusset by increasing weld length thereof. This can increase an area thereof and therefore lead to an increase in size and weight of the gusset.